As the most common dried fruit used in baking, raisins provide intense bursts of flavor. Dark raisins are made by sun-drying grapes, most commonly seedless Thompson grapes. Golden raisins, also known as sultanas, are made with the same grapes as dark raisins, but instead of sun-dried, the grapes are bleached with sulfur dioxide and then mechanically dried in a dehydrator, which produces a plump result. Store both types of raisins in covered containers at room temperature for up to a month or in the refrigerator for up to 6 months.